This invention relates generally to a truss fabrication system for fabricating trusses, and in particular to a truss fabrication system having readily adjustable legs.
Pre-manufactured structural frameworks, such as trusses, are widely used in the construction industry for forming a roof, wall panel, floor, or other building component because of their strength, reliability, low cost, and ease of use. The trusses are typically assembled in a factory using machinery for mass-fabrication of individual truss components. The trusses are assembled, for example, on large assembly tables and then shipped to construction sites. Each truss includes a collection of typically wooden truss members held together by connectors, such as nailing plates. In assembling trusses, the truss members are arranged on truss assembly setup tables, and nailing plates having nail-like projections or teeth extending from one side are placed at the intersections of the truss members with their teeth pointed toward the surface of the truss members. To facilitate efficient assembly of the truss, a roller or gantry press is used to press the nailing plates into the truss members. The gantry press travels along the table to press the nailing plates into the truss members thereby joining them together. The roller apparatus includes a cylindric roller, roller supports, and several wheels mounted on wheel guides along opposite sides of the table. After traversing the length of the table, the roller apparatus continues moving along the guides and is stopped in a parking area at an end of the table such that the assembled truss can be freely removed from the table without obstruction by the roller apparatus.
The installation of the table gantry press tracks is critical in the proper operation of the gantry press. The truss set-up table work-surface must be level and true with respect to the gantry press to uniformly press the nailing plates into the truss members along the entire length and width of the truss. Gantry press devices of the prior art unfortunately have a number of potential difficulties. For example, initial installation of the table to a perfectly level orientation can be time consuming. Additionally, uneven settling of the ground under the truss set-up table may cause the work surface to become misaligned with the gantry press. Normally, the truss set-up table is fixedly attached to the floor, usually by welding, to prevent movement or wobble of the truss set-up table. It has often been necessary to break the welds to correct any misalignment of the table.